Fill adjusting mechanism for molding presses



Jan. 9, 1951 R. B. SAALFRANK FILL ADJUSTING MECHANISM FOR MOLDINGPRESSES Filed Dec. 9, 1948 2 Sheets-Sheet 1 INVENTOR. R YAL B- SA LFRANK14 a aw T ORNEY Jan- 1951 I R. B. SAALFRANK 2,537,426

FILL ADJUSTING MECHANISM FOR MOLDING PRESSES Filed Dec. 9, 1948 2Sheets-Sheet 2 J TI? IN V EN TOR.

R ws; B. SP P LFRANK BY ATTO RNEY Patented Jan. 9, 1951 FILL ADJUSTINGMECHANISM FOR MOLDING PRESSES Royal B. Saalfrank, Philadelphia, Pa.,assignor to F. 3. Stokes Machine Company, a corporation of PennsylvaniaThis invention relates to molding presses, and

it is concerned especially with an arrangement for adjusting thefill ofthe press to vary the amount of material pressed into each moldedarticle, and also varying the stroke of the ejection of molded articlesof different thicknesses.

An object of the invention is to devise a mechanism by which theejection stroke of a press is adjusted with adjustment of the fill ofthe press to insure that the ejection punch or plunger will always comeflush with the die surface for different adjustments of fill.

Another object is to devise a mechanism of the type just described whichmay be adjusted while the press is in operation.

The present invention is an improvement over single punch presses now incommon use in which the fill of the press is adjustable by adjusting thevertical height of an anvil on which the lower plunger carrying thelower punch is seated during the filling and compressing stages of themolding cycle. In such machines, the ejection lever provided with aforked end embracing the lower plunger has a constant throw and engagesa collar on the lower plunger on its upward stroke to raise the lowerpunch to a position where its end is flush with the surface of the dietable. In molding thin tablets, the anvil is elevated until the end ofthe lower punch is only a small distance below the top surface of thedie, whereas in the case of thick tablets, the anvil is lowered untilthe end of the punch lies considerably below the top of the die. Sincethe ejection lever or fork has a constant throw, there will be more orless wind-cutting of the fork, depending upon the thickness of thetablet being molded. For very thick tablets, the fork cuts very littlewind, but for thin-tablets there is considerable wind-cutting.

Accordingly, a further object of my invention is to devise anarrangement for adjusting the fill of a molding press which eliminateswind-cutting of the ejection lever for all adjustments of Still anotherobject is to devise a mechanism for simultaneously adjusting theejection stroke of the press and the vertical position of the anvilwhich supports the ejection plunger during the compression stage of themolding cycle.

The invention is illustrated in the accompanying drawing in which Figure1 is a sectional view of the press taken along a vertical plane passingthrough the center of the press but showing only so much of the punch orplunger to secure proper ejection bears against wear plates "in theslot.

Application December 9, 1948, Serial No. 64,385 10 Claims. (01. 18-16)press as is necessary to explain the invention;

and

Figure 2 is a perspective view of the essential parts of the arrangementfor simultaneously adjusting the fill, the ejection stroke, and thevertical'position of the anvil of the press.

Referring to the drawing, l indicates a suitable frame which supportsthe die table 2 having a vertical die opening or cavity Z'a. A lowerpunch 3 is mounted with its upper end in the die cavity 2a and extendsdownwardly through a guiding bearing formed in frame part la. The pressincludes an upper punch 4 suitably mounted for reciprocation into theupper end of the die cavity 2, and since the arrangement for mountin andoperating this punch forms no part -ofthe present invention it is notdescribed herein. The lower end of the punch 3 rests upon the upper endof an anvil 5 at the point 3a, and the anvil is arranged to be adjustedin height by an arrangement to be described later.

The punch 3 normally rests upon the anvil 5 during the compressionportion of the molding cycle, and. is then moved upwardly to effectejection of the molded article from the die cavity. The arrangement foroperating the punch 3 during ejection involves a bell-crank 6pivotally'supported by a pin I on a yoke 8 which is mounted for verticaladjustment as will be explained later.

A horizontal arm 6a of the bell-crank 6 extends into a vertical slotformed in the lower end of the punch 3, and the rounded head of the armBa 31) and 30 positioned The vertical arm 6b of the bell-crank carries apin 9 at its upper end, and a slide I0 is pivotally mounted upon the pin9 on the far side of the arm as shown in Figure l. The slide It ispositioned between, and in sliding contact with, a pair of wear platesIla and Nb rigidly mounted 'in a recessed portion of a rock shaft !2having a rocking axis shown at l2a arranged parallel with and verticallyabove the pivotal axis of th bell-crank 6.

The shaft I2 is given a rocking or oscillating motion of constantamplitude following each compression stage in the molding cycle, and theoscillation of the shaft may be accomplished in any suitable manner. maybe provided with an arm or lever it which For example, the shaft haspivotally mounted on the end thereof a roller l4 which engages asuitably shaped cam operated in timed relation with the operation of theupper punch lto oscillate the shaft l2 after the upper punch iswithdrawn from the cavity following compression of the molded article.

Figure 1 shows the various parts of the press in their operativepositions during the filling of the die cavity, and also during thecompression stage of the molding cycle.

When the molded article is to be ejected, the cam follower it: rotatesrock shaft i2 clockwise through a given angle and this causes thebellcrank to be rocked counterclockwise, and the arm 6a of thebell-crank raises the lower punch 3 until its upper end is flush withthe top of the die table 2. After this, the rock shaft 12 is moved in acounterclockwise direction and returned to the position shown in Figurel, and the press is ready to receive another charge of molding material.

The arrangement for varying the fill of the press comprises anarrangement for raising or lowering the yoke 8 which supports thebellcrank 6, and includes a threaded shank Be on the yoke 8 havingthreaded engagement with a sleeve 15 mounted for rotation about avertical axis in a bore 16 formed in the bottom portion of the frame I.The rotary axis of the sleeve 15 intersects the axis la of the pin 1 andthe axis 12a of the rock shaft i2, By rotating the sleeve 15 to lowerthe yoke 8, the normal position of the arm Ba will be lowered, and thestroke of the arm will be increased. Conversely, by rotating sleeve IEto raise the yoke 8, the stroke of the arm will be decreased.

As the stroke of the arm 6a is changed, it is also necessary to changethe position of the anvil 5 which supports the lower end of the lower 2plunger 3 during the filling and compressing stages of the moldingcycle, and this is accomplished by mounting the anvil 5 in screwthreaded engagement with a rotary sleeve I'l positioned within avertical bore formed in the lower wall of the frame l.

Sleeves l5 and ii are rotated simultaneously by a gear train comprisinggears I50, and I'm secured respectively to the upper ends of the sleevesl5 and ii, and an intermediate idler gear 18 journaled on a stub shaft19 secured in the lower wall of the frame I. The gear train may beoperated by a. suit-able arrangement involving a pinion 29 secured to avertical shaft 2| which is journaled at its upper and lower ends insuitable bearings formed in frame i and is provided near its upper endwith a bevel gear 22 meshing with a second bevel gear 23 carried by ahorizontal shaft 24 journaled in the front wall of frame I and carryinga hand wheel 25 mounted on its outer end. By turning hand wheel 25 inone direction or the other, the sleeves l5 and I! may be rotated in onedirection or the other to simultaneously raise or lower the yoke 8 andthe anvil 5.

The anvil 5 must be held against rotation, and for this purpose an arm26 is secured within a transverse slot formed in the upper end of anvil'5 and is provided with a forked end embracing the shaft 2!. Thisarrangement is clearly shown in Figure 2, and it serves to preventrotation of the anvil 5 while permitting axial movement thereof.

Yoke 8 supporting the ejection lever B may be held against lateraldeflection during ejection by means of a pair of bosses 81) havingvertical faces which bear against a vertical wall portion ie of theframe 5. This arrangement permits vertical movement of the yoke whilerestraining it against lateral movement during ejection operation. Thethreaded sleeve I5 is retained in 4 7 its hearing b means of an anglepiece lb clamped to the lower wall of the frame I and engaging the upperface of the gear Mia, and also by a circular plate [9a, mounted on theupper end of stud [9.

In the normal position of the rock shaft 12 as shown in Figure 1 withthe axis of lever 13 in the position A, the wear plates Ha and libforming a guide for the sliding block iii are inclined to the verticalby a given angle as shown.

The rock shaft l2 has a constant angle of rock or oscillation from theposition shown in Figure l to a position where the wear plates Ha and Nbare inclined to the vertical, on the opposite side thereof, andpreferabl by the same angular amount. The arrangement is such that whenthe yoke 8 is elevated to a point where the axis ila of the pin 9coincides with the rotary axis 12a of the shaft [2, the upper end of thepunch 3 will be flush with the upper surface of the table 2, andoscillation of the rock shaft will not cause any movement of the punch3. This is the position of adjustment for zero fill of the press.

As the yoke 8 is moved downwardly to increase the separation of the pinaxis So from shaft axis (2a, the angle of oscillation of the bell-crank5 is increased, and the stroke of the punch 3 is correspondinglyincreased.

Operation of the arrangement shown in the drawing is believed to beclear from the foregoing description, but may be summarized as follows:

Following the compression step in each molding cycle, rock shaft 12 isoscillated or rocked through a constant angular movement from the normalposition shown in Figure 1 with the axis of lever l3 in the position Ato the position B where the wear plates [la and Nb are inclined to thevertical in the opposite direction from that shown in Figure 1, andpreferably by the same angular amount. These wear plates in combinationwith the slide ll] constitute an oscillating lever operated by the shaft52 and having a variable length determined by the vertical adjustment ofthe yoke 3. As shown in Figure 1, the length of the lever arm isthe'distance between the axis to of the pin 9 and the axis 12a oftheshaft l2. As this lever arm is moved from the inclined position shown inFigure 1 to the oppositely inclined position, the bell-crank 6 will berotated in a counter-clockwise direction to a position where the upperend of the punch 3 is flush with the upper surface of the die table .2,and the ejected article is in a position to be pushed across the dietable by the feeding shoe, not shown. If the fill of the press isincreasedby lowering the yoke 8, the length of the oscillating leverSci-42a will be increased, and this will result in a greater angularoscillation of the bellcrank, and a greater throw of the punch 3.

In order that the lower end of the punch 3 should maintain contact withthe upper end of the anvil 5 for different adjustments of the fill, anumber of design factors must be related, including the pitch of thethreads on anvil 5 and yoke shank 8a, and the ratio of the arm lengthson bell-crank '5 and the angle of inclination of the lever 9a--I2a inthe normal position of shaft 12. The drawing shows only one arrangementamon a number of possible arrangements, in which the arm 6a is twice thelength of the arm to and the pitch of the threads on anvil 5 is twicethe pitch of the threads on yoke shank Ba. With this arrangement,contact is maintained between the lower end of punch 3and the anvil 5 byarrang ing the angle of the lever Sa-lZa so that the axis 911 of the pin9 is deflected laterally from the vertical by one-half the verticalmovement of the yoke 8. In this case, the angle to the vertical will beapproximately 26.5 degrees. With this arrangement, the punch 3 willalways move toa position where the upper end thereof is flush with thetop of the table 2 when the arm I3 is in position B and the arm 9ai2a isinclined to the vertical on the opposite side thereof and by the sameangle.

1 The angle of the arm sci-ma in the position A of the lever is may bechanged by changing the pitch of the threads on anvil 5. For example, ifthe arm 9a-i2a is in a vertical position normally, the threads on anvil5 would have the same pitch as the threads on shank 8a, but the extentof angular oscillation of the arm 53 would be reduced to one-half of thethrow formerly employed, that is, it would be reduced to approximately26 5 degrees instead of approximately 53. Also, it is obvious that inthe arrangement shown in the drawing the correct ratio of verticalmovement of the anvii 5 with respect to the yoke 8 may be obtained byusing threads of equal pitch on these two elements and by'selecting theproper gear ratio between gears I511 and He.

While I have described and shown one specific embodiment of my inventionand have given specific ratios of arm lengths, angles and threadpitches, it will be understood that this design data has been given forthe purpose of explain. ing the principle of my invention and not by wayof limitation.

K I claim:

1. In a molding machine, the combination of a die having a verticalbore, a punch entering the lower end of said bore and H101 d forreciprocation in said bore, an anvil mounted vertical adjustment belowsaid punch and serving to support said punch during the compressingstage of a molding cycle, a bell-crank lever pivoted on a horizontalaxis and having a horizontal arm and a vertical arm, a connectionbetween said horizontal arm and said punch for reciprocatin said punch,a rocinshaft mounted on a horizontal axis in the same vertical plane asthe axis of said bell-crank lever and having a rocking lever arranged inoverlapping relation with the vertical arm of said bell-crank, meanspivotally connecting said vertical arm with said rocking lever andhaving sliding contact with said rocking lever to permit variation inthe length thereof, adjustable means for varying the separation betweenthe pivotal axis of said bell-crank and said rock shaft to thereby varythe effective length of said rocking lever, and common means foroperating said adjustable means and for simultaneously adjusting theheight of said anvil.

2. A machine according to claim 1 wherein said rocking lever has a fixedangular throw and in one end position of the throw the lever is inclinedat an angle to the vertical such that the upper end of said punchremains flush with the upper end of said die for all variations in thelength of said rocking lever.

3. In a molding machine, the combination of a die having a verticalbore, a punch entering the lower end of said bore and mounted forreciprocation in said bore, an anvil mounted for vertical adjustmentbelow said punch and serving to support said punch during thecompressing stage of a molding cycle, a bell-crank lever pivoted on ahorizontal axis and having a horizontal arm and zontal arm and saidpunch for-"reciprocating said punch, a rock-shaft mounted on ahorizontal axis in the same vertical plane asthe axis of said bellcranklever and having a rocking lever arranged in overlapping relation withthe vertical arm of said bell-crank, means pivotally connecting saidvertical arm with the lever on said rock shaft, said means havingsliding contact with one of said connected levers to permit variation inthe length of said one lever, adjustable means for varying theseparation betweenlthe pivotal axis of said bell-crank and saidrock-shaft to thereby vary the effective length of said one leveiyandcommon means for operating said adjustable means and for simultaneouslyadjusting the height of said anvil.

4. In a molding machine, the combination of a die having a verticalbore, a punchv entering the lower end of said bore and mounted forreciprocation in said bore, a bell-crank lever pivoted on a horizontalaxis and having a horizontal arm and a vertical arm, a connectionbetween said horizontal arm and said punch for reciprocating said punch,a rock-shalt mounted on a horizontal axis in the same vertical plane asthe axis of said bed-crank lever and having a rocking lever arranged inoverlapping relation with the vertical arm of said bell-crank, meanspivotally connecting said vertical arm with the lever on said rockshaft, said means having sliding contact with one of said connectedlevers to permit variation in the length of said one lever, and adustable means for varying the separation between the pivotal axis ofsaid bell-crank and said rock shaft to thereby vary the effective lengthof said one lever. V

5. In a molding machinathe combination of a die having a vertical bore,a punch positioned in the lower end of said bore and mounted forreciprocation in said bore, a bell-crank lever pivoted on a horizontalaxis and having a horizontal arm and a vertical arm, a connectionbetween said horizontal arm and said punch for reciprocating said punch,a rock shaft having a fixed angular throw and being mounted on ahorizontal axis in the same vertical plane as the axis of saidbell-crank, a rocking lever carried by said rock shaft and arranged inoverlapping relation with a vertical arm of said bell-crank, meanspivotally connecting said vertical arm with said rocking lever, saidmeans having sliding contact with said rocking lever to permit variationin the effective length thereof, and adjustable means for varying theseparation between the pivotal axis of said bell-crank and the axis ofsaid rock shaft to thereby vary the effective length of said rockinglever, said rocking lever being arranged so that in one end position ofits throw, it is inclined at an angle to the vertical such that theupper end ofsaid punch remains flush with the upper end of said die forall variations in the distance of separation'between the pivotal axis ofthe bell-crank and the axis of the rock shaft.

6. A molding machine according to clam 5 wherein the vertical arm ofsaid bell-crank is one-half the length of the horizontal arm, and saidrocking lever, in said one end position, is inclined to the vertical byan angle of substantially 26.5 degrees.

7. In a molding press, the combination of a die having a vertical bore,a punch entering the lower end of said bore and mounted forreciprocation in said bore, an anvil arranged below said punch andmounted for vertical adjustment below said punch and serving to supportsaid punch a vertical arm, a. connection between said horiduring thecompressing stage of the molding cycle, an ejection lever, means tooscillate said lever, a. connection between said lever and said punch tomove said punch in reciprocating movement throughout the oscillation ofsaid even means to adjust the extent of throw of said oscillating lever,and common means for operating said throw adjusting means to increasesaid throw and for simultaneously lowering said anvil.

8. In a molding press, the combination of a die having a vertical bore,a punch entering the lower end of said bore and mounted forreciprocation in said bore, an anvil mounted for vertical adjustmentbelow said punch and serving to support said punch during thecompressing stage of the molding cycle, an ejection lever, a rockinglever having a fixed angular throw, a connection between said rockinglever and said ejection lever to reciprocate said punch throughout theoscillation of said rocking lever, means for shifting said connectionalong one of said levers to vary the efiective length thereof andthereby vary the throw of said punch, and common means for operatingsaid throw varying means to increase said throw and for simultaneouslylowering said anvil.

9. In a molding press, the combination of a die having a vertical bore,a punch entering the lower end of said bore and mounted forreciprocation in said bore, an anvil arranged below said punch andmounted for vertical adjustment and serving to support said punch duringthe compression stage of the molding cycle, a pivoted lever, means tooscillate said lever, a connection between said lever and said punch formoving said punch throughout the oscillation of said lever toreciprocate said punch between an upper position where the end of thepunch is flush with the upper end of said bore and a lower position,means for adjusting the throw of said lever to maintain the same upperposition of said punch while lowering the lower position thereof, andmeans operable simultaneously with said throw adjusting means for movingsaid anvil vertically to maintain said anvil substantially in contactwith said punch in its lower position for difierent adjustments of saidthrow adjusting means.

10. In a molding press, the combination of a die having a vertical bore,a punch positioned in the lower end of said bore and mounted forreciprocation in said bore, an anvil arranged below said punch andmounted for vertical adjustment, a lever having a fixed pivot betweenthe ends thereof, an adjustable stroke rocker element connected to oneend of said lever and serving to oscillate said lever, a connectionbetween the other end of said lever and sa (1 punch for moving saidpunch throughout the oscillation of said lever to reciprocate said punchbetween an upper position and a lower position, means for adjusting thestroke of said rocker element to vary the throw of said punch whilemaintain'ng the end of the punch level with the top of the die in theupper position of said punch, and means operable simultaneously withsaid stroke adjusting means for moving said anvil vertically to maintainsaid anvil substantially in contact with said punch in its lowerposition for different adjustments of throw of said punch.

ROYAL B. SAALFRANK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 686,765 Richards Nov. 19, 1901876,388 Nieters Jan. 14, 1908 1,295,760 Klay Feb. 25, 1919 2,232,180 KuxFeb. 18, 1941

